1. Technical Field
The present invention relates to scupper joints for ships. More particularly, the present invention relates to a scupper joint provided at a lower lateral portion of a ship hull, wherein the scupper joint is connected with a pumping plant installed in the ship hull for allowing water drawn by the pumping plant to be discharged out of the ship hull through the scupper joint.
2. Description of Related Art
Referring to FIG. 1, on a ship, a plurality of scupper joints 1 provide at a lower lateral portion of a ship hull are connected with a pumping plant in the ship. The pumping plant serves to draw water from a bottom tank or a cooling system of the ship and discharge the water out of the ship through the scupper joints 1.
The conventional scupper joint, as shown in FIG. 2, comprises a tubular body 10 and a locking ring 11 that is mounted around and thereby coupled with the body 10. The body 10 is axially, centrally formed with a through hole 101. The body 10 is also peripherally formed with a flange 12, a threaded segment 13 and a connecting segment 14. Another threaded segment 111 is formed at an inner periphery of the locking ring 11 for getting coupled with the threaded segment 13 of the body 10. By screwing the locking ring 11, the locking ring 11 is tightened and moves along the threaded segment 13 of the body 10 so that adjacent surfaces 122, 112 of the flange 12 and the locking ring 11 pressingly abut against an inner lateral 191 and an outer lateral 192 of a hull 19 of the ship, respectively. Some protrusions 141 are formed at an outer periphery of the connecting segment 14 for facilitating combination between the connecting segment 14 and an external plastic pipe 15. When the plastic pipe 15 is further communicated with a pumping plant, water pumped by the pumping plant can be discharged out of the ship through the hole 101 of the body 10.
For preventing rust thereon, the body 10 and the locking ring 11 are usually made of stainless steel through a casting process and then processed to have the aforementioned threaded segments and protrusions. Since the casting process requires a long production cycle in addition to expensive modules, for satisfying buyers' unscheduled component demands, the manufacturing may have to produce for inventory, thus adding burden to inventory turnover and management. Besides, while being hedged about the availability of existing modules, provision of the products is far from flexible. On the other hand, through the casting process, it is difficult, if not impossible, to make the body 10 have a wall thickness less than 2 mm without causing a high defective rate.
Consequently, the resultant scupper joint is bulky and heavy, thus requiring increased packing and transporting costs.
Moreover, the body 10 made of stainless steel can still rust after long-term contact with water. As a result, the rust scales can block the hole 101 and significantly weaken the discharging capacity of the scupper joint, rendering a shortened service life of the scupper joint. In view of this, some known approaches have suggested further preventing rust by making the parts with anticorrosive metal materials, such as titanium alloy. However, the expensive materials make the products become too expensive to be classed as economical. Other processes, such as vacuum casting and powder metallurgy, have been proposed as alternative approaches to make the wall thickness of the body 10 thinner than 2 mm. Nevertheless, theses processes require remarkable costs in modules and operation as compared with the aforesaid casting process does. As a result, the expensive processes make the products become too expensive to be classed as economical.